Many medicaments, such as pharmaceutical drugs that are psychoactive or analgesic, have significant ability to cause euphoria or pleasurable effects, and are thereby at risk for abuse. In many instances such drugs are crushed, melted, dissolved or altered, and are then inhaled, snorted, injected or swallowed in a manner or dosage that is inconsistent with their intended or safe usage. Tampering of immediate release, or extended release formulations in particular, will rapidly deliver a bolus dose and produce a variety of serious and life threatening side effects, including respiratory depression and failure, sedation, cardiovascular collapse, coma, and death. Likewise, there are a number of medicaments that when administered at any level cause undesirable side effects, such as chemotherapeutics. Other medicaments, such as antibiotics, accumulate in the environment and may increase the evolution of antibiotic resistant organisms. It is important to dispose of such unused medication properly to prevent wrongful administration or contamination of wastewater treatment facilities.
Types of pharmaceutical drugs that are particularly targeted for tampering are those listed on Drug Enforcement Agency's Schedule II list, such as opioids, phenylephrine, stimulants like amphetamines and methylphenidate, benzodiazepines such as lorazepam (Alivan) and alprazolam (Xanax) and other types of drugs of abuse, which can be extracted from their dosage form in a variety of ways. For example, the dosage form can be mixed with a suitable solvent (e.g., water or alcohol), and then the drug can be filtered and/or extracted from the mixture for intravenous injection. Extended release dosage forms can be dissolved in water, alcohol or another “recreational solvent” to hasten the release of the drug, and then ingested orally; this provides high peak plasma concentrations of the drug and maximum euphoria effects. There is an enormous need to dispose of these drugs, especially opioids, safely since leftover opioids contribute to the steady increase of opioid abuse, overdoses and death in the past decade.1 
Other pharmaceuticals such as highly potent drugs (e.g., alprazolam and chlorpromazine) and drugs with strong side effect profiles such as chemotherapeutics (e.g., including, but not limited to bendamustine, cisplatin, paclitaxel, topotecan, thalidomide, lenalidomide and related substances) may be dangerous if administered accidentally and are harmful to the environment if disposed into the sewer or landfills. Other categories of problematic medicaments include antibiotics (e.g. including, but not limited to penicillins, cephalosporins, aminoglycosides, and sulfonamides), where chronic exposure beyond the intended recipient can enter the food chain or waste disposal system to result in antibiotic resistance. Other general categories of problematic medicaments include cardiovascular drugs (e.g., including, but not limited to antihypertensives and statins) and erectile dysfunction drugs (e.g., including, but not limited to Viagra®, Cialis®, and Levitra®).
Once the patient is done using medication, which often constitutes taking only a portion of the amount provided, the medication is often disposed of unchanged in the household waste or flushed down the toilet. Alternatively, leftover and expired medications can remain in the family or household medicine cabinet, available for both unintended used and abuse. Both of these medication endpoints have serious unintended consequences. If the product is disposed in the household waste or flushed into the sewer system, it can pass unchanged into the environment where it will likely create toxic effects on animals and cause an imbalance in the local ecosystem. This disposal of medicaments into wastewater and landfills has poisonous effects and is gaining wide opposition.2 In fact, the ramifications for the environment and human health with respect to drug disposal are currently under review by the U.S. Environmental Protection Agency (EPA), Office of Research and Development (ORD), National Exposure Research Laboratory (NERL), Environmental Sciences Division (ESD). The goal of the EPA and other organizations is to reduce the entry of active pharmaceutical agents into the environment, with the ultimate objective to minimize exposure (both chronic and acute) to humans and wildlife alike.3 
A major safety campaign is currently underway in the United States to dispose of drugs at risk for abuse in a manner that will prevent their misuse, either by accidental administration or by illicit use. The United States Food and Drug Administration (FDA), the Drug Enforcement Agency (DEA), and White House Office of National Drug Control Policy (ONDCP) offer guidance for unused pharmaceutical product disposal, which includes directions to flush drugs down the toilet or to mix drugs with coffee grounds to throw away, and encouragement to participate in “take-back” programs. This guidance, however, is dependent on consumer compliance and teaches processes that maintain environmental exposure or may lead to diversion. Further, the risks of the improper disposal of pharmaceutical agents beyond those listed above include legal liabilities to pharmaceutical companies, health care facilities and pharmacies that are increasingly being held responsible for the dangers posed by drugs that remain in medicine cabinets and not properly disposed.
There are many examples of centralized collection or mail-in pharmaceutical disposal systems that use traditional large-scale industry approaches for the sequestration and disposal of pharmaceutical agents. To be successful, such systems require substantive compliance from the consumer and create risks to the collectors, such as law enforcement or pharmacies, as they do not have tight control of the disposed or returned pharmaceutical agents (including scheduled drugs) that they receive.
As a result, a significant amount of these unused pharmaceuticals accumulate in consumers' homes, are abused by persons removing them from medicine cabinets, are released into the environment through disposal into the water system as recommended by the FDA, are misused by persons other than those receiving the prescription, or are diverted to illegal trade channels.
Another approach is to dispose of unused pharmaceutical agents using a secondary containment distributed collection system. These systems involve emptying unused drugs into a pouch, bag or bottle that contains sequestering or aggregating agents, or emptying a second container with such agents into a first container and adding water.4 
Psychoactive medicaments are of particular concern, as there are two major ways that unused psychoactive medicaments can cause harm. The first, described above, are the unsafe methods of disposing unused medicaments that can then be channeled to improper use or cause harm to the environment. The second is to attempt to extract the active ingredients of psychoactive medicaments for the purpose of abuse.
To prevent misuse of medicaments, especially drugs at risk for abuse, various technologies have been developed. One approach is to combine in the same pharmaceutical formulation the active agent and a second agent that is capable of limiting the psychotropic effect of the active agent when the formulation is taken parenterally. An example is a combination of methadone, an opioid agonist, and naloxone, an opioid antagonist, that if simultaneously administered, would result in minimal or no opioid effects by the abuser.5 
Approaches have also been developed that target preventing the tampering of opioids. For example, one method is to inter-disperse an opioid and an antagonist in a pharmaceutical formulation, such that the antagonist is “sequestered” in a form that prevents it from being released when the medicinal product is taken by its normal oral route.6 However, a concern regarding this approach is that the necessary chemical association of the two compounds can lead to a complex manufacturing process and high production costs. Also, leaching of the antagonist into the bloodstream can block the desired pain relieving therapeutic effect of the opioid.
Another approach is a dosage form in which the opioid is associated with an antagonist and an irritant that is sequestered in a closed compartment, such that tampering with the dosage form leads to release of the irritant.7 Yet, preparation of this dosage form requires the association of three active agents and the creation of compartments, which makes its manufacture complex and more costly than a simple dosage form such as a tablet.
Another approach is to add a bad smelling agent to the opioid, such that attempts to inhale the active agent would be thwarted.
Other approaches do not involve an association of the opioid or active substance with an antagonist, but rather the dosage form is manufactured wherein the opioid forms a salt with one or more fatty acids, thereby increasing its lipophilicity and preventing its immediate release if the pharmaceutical form is tampered. 8 This type of dosage form requires chemical conversion of the active agent.
A general issue with the approaches named above is that the manufacturer must take the time to incorporate, test, and gain approval from the FDA to obtain claims that would enable the marketing of such abuse deterrent technologies, which can take 5-10 years or work to produce. There are numerous drugs on the market right now for which an abuse deterrent system is only partially effective or will never be incorporated into the products. These drugs will continue to harm people, and this issue is becoming a public health concern across the United States.
Another issue that applies to the approaches that are not abuse deterrent technology incorporated into the dosage form, i.e., as separate collection compositions, is that they are limited in the amount of drug they can absorb. For instance, activated charcoal in disposal compositions are often difficult to wet, which can lead to lack of mixing with the drug product and may prevent absorption of the intended drug substance. Moreover, the products can be inconvenient to obtain, because they must be ordered separately from the purchase of the prescription.
There is therefore a need for a convenient and widely distributed or easily obtainable disposal composition that allows for the safe disposal of medicaments that are expired or no longer needed by the patient to whom the product was intended or prescribed. The need to develop an effective disposal means of such products will become greater as the drugs become more commonly prescribed to treat ageing populations where cancer, pain and other conditions increasingly prevail. Over the last decade, fatal prescription drug poisonings (abuse and accidental) have increased 5-fold. In 2010, of the 38,329 drug overdose deaths reported by the Center for Disease Control (CDC), almost 60% or 22,000 deaths were related to prescription drugs. Over 70% of prescription drug abusers acquire their drugs from friends or relatives without permission (i.e., home medicine cabinets). Trends for teen prescription drug abuse continue to outpace any other drug use except marijuana.
The disposal of unwanted drugs within the current regulatory and legal framework is complex and ineffective. This is largely due to the restrictive handling of controlled substances and the conflicting recommendations from the Food and Drug Administration (FDA), the Drug Enforcement Administration (DEA), and the Environmental Protection Agency (EPA). As reviewed above, according to the FDA's website “How to dispose of unused medicines,” leftover medications should be flushed down the toilet, thrown into the trash, or taken to drug “take back” programs in the community. These alternatives have the potential to harm the environment or result in diversion for illicit use, and “take back” programs offered by the DEA are an inconvenience and do not encourage compliance. In California and Washington, laws are now in place, which hold both the drug companies and pharmacies responsible for the leftover drugs in the patient's medicine cabinet.
Thus, an effective disposal composition for unused drugs of abuse such as opioids, psychoactive medicaments and other therapeutics is a critical unmet need to ensure safety for patients and the environment.